| Message ID | 20230427192642.1115224-1-bb@ti.com |
|---|---|
| State | Changes Requested |
| Delegated to: | Tom Rini |
| Headers | show |
| Series | arm: mach-k3: am625_init: Add Erratum WA for RTC startup | expand |
On 14:26-20230427, Bryan Brattlof wrote: > From: Nishanth Menon <nm@ti.com> > > Add erratum i2327 work around for initialization for RTC > interrupt where interrupt is stuck for ever at startup. Unfortunately, > this workaround needs to be applied under 1 second of boot. > > Signed-off-by: Nishanth Menon <nm@ti.com> > [bb@ti.com: rebased from 2021.01] > Signed-off-by: Bryan Brattlof <bb@ti.com> > --- It will be good to state in the diffstat that am62a7 or other k3 SoCs are not impacted: am62a7 has the hardware fix and other SoCs do not have this rtc. I dont think there is a need to respin the patch for that - just clarifying. > arch/arm/mach-k3/am625_init.c | 44 +++++++++++++++++++++++++++++++++++ > 1 file changed, 44 insertions(+) > > diff --git a/arch/arm/mach-k3/am625_init.c b/arch/arm/mach-k3/am625_init.c > index a91c15ca4e188..e90c18fdcc118 100644 > --- a/arch/arm/mach-k3/am625_init.c > +++ b/arch/arm/mach-k3/am625_init.c > @@ -15,6 +15,15 @@ > #include <dm/uclass-internal.h> > #include <dm/pinctrl.h> > > +#define RTC_BASE_ADDRESS 0x2b1f0000 > +#define REG_K3RTC_S_CNT_LSW (RTC_BASE_ADDRESS + 0x18) > +#define REG_K3RTC_KICK0 (RTC_BASE_ADDRESS + 0x70) > +#define REG_K3RTC_KICK1 (RTC_BASE_ADDRESS + 0x74) > + > +/* Magic values for lock/unlock */ > +#define K3RTC_KICK0_UNLOCK_VALUE 0x83e70b13 > +#define K3RTC_KICK1_UNLOCK_VALUE 0x95a4f1e0 > + > /* > * This uninitialized global variable would normal end up in the .bss section, > * but the .bss is cleared between writing and reading this variable, so move > @@ -71,6 +80,40 @@ static __maybe_unused void enable_mcu_esm_reset(void) > writel(stat, CTRLMMR_MCU_RST_CTRL); > } > > +#if defined(CONFIG_CPU_V7R) > + > +/* > + * RTC Erratum i2327 Workaround > + * Due to a bug in initial synchronization out of cold power on, > + * IRQ status can get locked infinitely if we do not: > + * a) unlock RTC > + * > + * This workaround *must* be applied within 1 second of power on, > + * So, this is closest point to be able to guarantee the max > + * timing. > + */ > +void rtc_erratumi2327_init(void) > +{ > + u32 counter; > + > + /* > + * If counter has gone past 1, nothing we can do, leave > + * system locked! This is the only way we know if RTC > + * can be used for all practical purposes. > + */ > + counter = readl(REG_K3RTC_S_CNT_LSW); > + if (counter > 1) > + return; > + /* > + * Need to set this up at the very start > + * MUST BE DONE under 1 second of boot. > + */ > + writel(K3RTC_KICK0_UNLOCK_VALUE, REG_K3RTC_KICK0); > + writel(K3RTC_KICK1_UNLOCK_VALUE, REG_K3RTC_KICK1); > + return; > +} > +#endif > + > void board_init_f(ulong dummy) > { > struct udevice *dev; > @@ -78,6 +121,7 @@ void board_init_f(ulong dummy) > > #if defined(CONFIG_CPU_V7R) > setup_k3_mpu_regions(); > + rtc_erratumi2327_init(); > #endif > > /* > > base-commit: a25dcda452bf6a6de72764a8d990d72e5def643d > -- > 2.40.0 >
diff --git a/arch/arm/mach-k3/am625_init.c b/arch/arm/mach-k3/am625_init.c index a91c15ca4e188..e90c18fdcc118 100644 --- a/arch/arm/mach-k3/am625_init.c +++ b/arch/arm/mach-k3/am625_init.c @@ -15,6 +15,15 @@ #include <dm/uclass-internal.h> #include <dm/pinctrl.h> +#define RTC_BASE_ADDRESS 0x2b1f0000 +#define REG_K3RTC_S_CNT_LSW (RTC_BASE_ADDRESS + 0x18) +#define REG_K3RTC_KICK0 (RTC_BASE_ADDRESS + 0x70) +#define REG_K3RTC_KICK1 (RTC_BASE_ADDRESS + 0x74) + +/* Magic values for lock/unlock */ +#define K3RTC_KICK0_UNLOCK_VALUE 0x83e70b13 +#define K3RTC_KICK1_UNLOCK_VALUE 0x95a4f1e0 + /* * This uninitialized global variable would normal end up in the .bss section, * but the .bss is cleared between writing and reading this variable, so move @@ -71,6 +80,40 @@ static __maybe_unused void enable_mcu_esm_reset(void) writel(stat, CTRLMMR_MCU_RST_CTRL); } +#if defined(CONFIG_CPU_V7R) + +/* + * RTC Erratum i2327 Workaround + * Due to a bug in initial synchronization out of cold power on, + * IRQ status can get locked infinitely if we do not: + * a) unlock RTC + * + * This workaround *must* be applied within 1 second of power on, + * So, this is closest point to be able to guarantee the max + * timing. + */ +void rtc_erratumi2327_init(void) +{ + u32 counter; + + /* + * If counter has gone past 1, nothing we can do, leave + * system locked! This is the only way we know if RTC + * can be used for all practical purposes. + */ + counter = readl(REG_K3RTC_S_CNT_LSW); + if (counter > 1) + return; + /* + * Need to set this up at the very start + * MUST BE DONE under 1 second of boot. + */ + writel(K3RTC_KICK0_UNLOCK_VALUE, REG_K3RTC_KICK0); + writel(K3RTC_KICK1_UNLOCK_VALUE, REG_K3RTC_KICK1); + return; +} +#endif + void board_init_f(ulong dummy) { struct udevice *dev; @@ -78,6 +121,7 @@ void board_init_f(ulong dummy) #if defined(CONFIG_CPU_V7R) setup_k3_mpu_regions(); + rtc_erratumi2327_init(); #endif /*